From ae0202d6da9752710487054c86fdfdffc26e00b7 Mon Sep 17 00:00:00 2001
From: Maciej Ziarkowski <maciej.ziarkowski@gmail.com>
Date: Tue, 17 Sep 2019 18:01:48 +0100
Subject: [PATCH] Add blank, branching renderers

---
 app/src/tiles/renderers/blankRenderer.ts     | 21 ++++++++++++++++++
 app/src/tiles/renderers/branchingRenderer.ts | 23 ++++++++++++++++++++
 2 files changed, 44 insertions(+)
 create mode 100644 app/src/tiles/renderers/blankRenderer.ts
 create mode 100644 app/src/tiles/renderers/branchingRenderer.ts

diff --git a/app/src/tiles/renderers/blankRenderer.ts b/app/src/tiles/renderers/blankRenderer.ts
new file mode 100644
index 00000000..2d3187ed
--- /dev/null
+++ b/app/src/tiles/renderers/blankRenderer.ts
@@ -0,0 +1,21 @@
+import { Image } from "mapnik";
+import sharp from 'sharp';
+
+import { TileParams, TileRenderer } from "../types";
+
+class BlankRenderer implements TileRenderer {
+    getTile(tileParams: TileParams): Promise<Image> {
+        return sharp({
+            create: {
+                width: 1,
+                height: 1,
+                channels: 4,
+                background: { r: 0, g: 0, b: 0, alpha: 0 }
+            }
+        }).png().toBuffer();
+    }
+}
+
+export {
+    BlankRenderer
+};
diff --git a/app/src/tiles/renderers/branchingRenderer.ts b/app/src/tiles/renderers/branchingRenderer.ts
new file mode 100644
index 00000000..ce7d78da
--- /dev/null
+++ b/app/src/tiles/renderers/branchingRenderer.ts
@@ -0,0 +1,23 @@
+import { Image } from "mapnik";
+
+import { TileParams, TileRenderer } from "../types";
+
+class BranchingRenderer {
+    constructor(
+        public branchTestFn: (tileParams: TileParams) => boolean,
+        public trueResultTileRenderer: TileRenderer,
+        public falseResultTileRenderer: TileRenderer
+    ) {}
+
+    getTile(tileParams: TileParams, dataParams: any): Promise<Image> {
+        if(this.branchTestFn(tileParams)) {
+            return this.trueResultTileRenderer.getTile(tileParams, dataParams);
+        } else {
+            return this.falseResultTileRenderer.getTile(tileParams, dataParams);
+        }
+    }
+}
+
+export {
+    BranchingRenderer
+};